<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
</head>

<body>
  <div id = "app">
    {{msg}}
  </div>

  <script>
    const app = new Vue({
      data:{
        msg:"使用$mount()指定要控制的区域"
      }
    }).$mount("#app")
  </script>
  </div>
</body>
</html>